a(n) = (n+1)*A000521(n)/24.A161395a(n) = (n+1)*A000521(n)/24.Terms a(0) =0a(1) =31a(2) =16407a(3) =2686720a(4) =144049995a(5) =4217886720a(6) =83300660150External referencesoeis: A161395